/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.db.conf.directories.strategy;

import org.apache.iotdb.commons.utils.JVMCommonUtils;
import org.apache.iotdb.db.exception.DiskSpaceInsufficientException;

import java.io.IOException;

public class MinFolderOccupiedSpaceFirstStrategy extends DirectoryStrategy {

    @Override
    public int nextFolderIndex() throws DiskSpaceInsufficientException {
        return getMinOccupiedSpaceFolder();
    }

    private int getMinOccupiedSpaceFolder() throws DiskSpaceInsufficientException {
        int minIndex = -1;
        long minSpace = Long.MAX_VALUE;

        for (int i = 0; i < folders.size(); i++) {
            String folder = folders.get(i);
            if (!JVMCommonUtils.hasSpace(folder)) {
                continue;
            }

            long space = 0;
            try {
                space = JVMCommonUtils.getOccupiedSpace(folder);
            } catch (IOException e) {
                logger.error("Cannot calculate occupied space for path {}.", folder, e);
            }
            if (space < minSpace) {
                minSpace = space;
                minIndex = i;
            }
        }

        if (minIndex == -1) {
            throw new DiskSpaceInsufficientException(folders);
        }

        return minIndex;
    }
}
